Carbon Dioxide Corrosion of L-80 Grade Tubular in Flowing Oil-Brine Two-Phase Environments

The sweet corrosion behavior of L-80 grade downhole tubular was investigated in flowing two-phase oil-brine fluids. Depending upon percent water cut, two different phases appeared to exist: a water-continuous phase above 50% water cut and an oil-continuous phase below 50% water cut. In the oil-continuous phase, the presence of local turbulence and the staying time of water droplets on the steel surface were the overriding facyors determining the severity of the corrosion. The corrosion in the water-continuous phase was predominantly controlled by flow character and temperature. Based on this observation, a corrosion mechanism is proposed and discussed in this paper.